Internal brake mechanism.



A. P. BRUSH.

INTERNAL BRAKE MECHANISM- APPLICATION FILED FEB. 15. 1911.

1 86343. Patented June 13, 191 I 5 its entire length, the means beingsuch that ALANSON P. BRUSH, 0F FLINT, MICHIGAN. I i

INTERNAL IB miicnnmsn.

all whom it may concern:

' Be it known that I, ALANSQN P. BRUSH, a citizen of the United States,residin at Flint, in the county of Genesee and tate of Michigan, haveinvented a certain new and useful Improvement, in Internal BrakeMechanism, of which the following is a full, clear, and exactdescription.

My invention relates to friction brakes of the type which employ a splitfloating friction band within a rotating brake drum, a fixed stoplocated betweenthe ends of said band to limit its rotation with thedrum, and means for expanding said band to cause it to frictionallyengage said drum. The means heretofore used, and with which I amfamiliar, for expanding said split brake bands are either such (1) thatexcessive radial pressure is applied to the end portions of the bands,whereby these end portions will engage the drum before other parts ofthe band do, and will produce excessive braking action and excessivewear upon said end portions (the. radially acting wedges or theirequivalents being examples of means which produce such results), or, (2)such that the ends portions of the band are caused to bear unequallyagainst the drum (the use of cams between the ends'of the band beingexamples of means which produce this result),

The object of this invention is to provide means through which the brakeband may expand in such wise that the engagement of the band with thedrum will take place at approximately the same time throughout they willnot interfere with the desired selfsetting action of-said brake bandswhen the initial engagementof the band and drum has been brought about,

Broadly speaking, the inventionfconsists of brake band expanding meansadapted to apply to the end portions of said bands pressure'insubstantially tangential directions.

It also consists in the combinations of elements shown in the drawingand hereinafter described and definitely pointed outin the claims,

Reference should be had to the accompanying drawings forming a part ofthis specification in which- Figure 1 is a side elevation with certainportions of the brake drum removed, and showing my friction brake. Fig.2 is a section upon the line 2-2 of Fig. 1; and Fig.

Specification of Letters'lPatent.

Patent ed June is, rare.

Application filed February 15, 1911. Serial No. 608,664. g

3 is a view similar to Fig. 1, showing a modified form of the device. I

A rotating shaft is represented at 1 tov 6 of said band, and limits therotary move- 1' ,1

ment of said brake band with the drum.

This stop is a part of a bracket 8 projecting from the tubularnon-rotating support 9 in which is the bearing for the rotary member,

of which the brake drum is a part.

Through the lower portion of the bracket 8, a short shaft 10 extends, toone end of "which is secured a lever 11 which may be connected with anysuitable operating mechanism through the intermediary of the rod 12. Twolevers 13 and 14 are pivoted upon the shaft 10, or any other supportingshaft carried by said bracket; and in the form shown in Fig. 1, theselevers assume the shape of bell crank levers with their free ends 13 and14 of hook like form, which pass between and bear respectively upon theends 6 and'5 of the brake band. A pair of toggle levers 15 and 16 arepivoted to each other at one of their ends, and at their opposite endsare pivoted upon the arms 13 and 14. There is a rod 17 which ispivotally con nected with the levers 15 and 16 at the point where theyjoin, and this rod 17 at its opposite end is pivoted upon an arm 18which 1s made fast upon the shaft 10.

The operation will be clear from the disclosure, for when the rod- 12 ispulled, motion is transmitted to lever 11, and from it to shaft 10,whereby arm 18 causes the rod 17 to move so as to swing the levers 15and 16 toward the toggle straightening position.

This action will causethe arms 13 and '14 to be spread apart and toapply pressure, in a substantially tangential direction, to' the ends ofthe brake band 4; and this will produce such uniform enlargement of thebrake band that all parts of it will engage atapproximately the sameinstant with the. projects between tion of the brake whichever directionthe drum is rotating in. In fact, the described brake has all of thedesirable qualities of the brakes heretofore used in which the splitband is expanded by a wedge, and it hasla-lso the added advantage thatthe band engages uniformly throughout its entire periphery. This isbecause the levers 13 and 14 being pivoted, must move in the arcsof'circles and therefore whatever pressure they may apply under anycondition of use will be applled in a direction substantially tangentialto the brake band at the ends thereof, and

, the force acts only to spread the ends, and

doesnot push the ends radially into contact 7 with the drum.

In the form shown in Fig. 3, the same general construction is-observed,with the exceptionthat the levers 13 and 14 are not bell crank levers.Instead the free ends of I these levers are pivotally connected with butin other respects the construction is the.

same; and the action is also the same 111 that f as links 19 and 20which in turn are pivotally connected with the ends of the brake band 4,

it applies the spreading force to the brake band in the substantiallytangential direction referred to.

It is to be understood that various mechanisms maybe employed forspreading the arms 13 and l4,and for transmitting movement from thesearmsto the ends of the brake band, provided the latter mechanism is suchas to impart the' substantially tangential band.

Having thus described my invention, What I claim is p 7 1.The'combination of a brake drum, an expansible split brake band withinsaid drum,

movement to the end of the brake a fixed stopz-located between the endsof the v brake band and serving by engagement with one end or the otheras the sole means to prevent the brake band fromturning, two

' movable devices for spreading apart the ends of said brake band, eachof which devices engages-the brake band near one end thereof and extendsaway from that point of engagement and away from the other movabledevice, and means acting on said devices at points remote from theiradjacent ends for drawing apart said devices and therefore the ends ofthe brake band.

2. The combination with a brake drum, of a split brake-band withintheflange', a stop between the ends of said band, a pair of arms pivotedupon a fixed support, each with the'ends of the brake band, a toggleoperatively connecting said arms, and means for operating the toggle.

4. The combination with a support, a fixed bracket, a rotating brakedrum adjacent to the bracket, a split expansible brake band within saiddrum, a shaft mounted in said bracket, a pair of arms looselymounted-upon said shaft, there being operative connections between thefree end of each of said arms and an end-0f the of said arms beingoperatively connected I brake band, a toggle for spreading said arms, arod for operating the toggle, and an arm connected with the shaft andwith said rod, and 'an operating arm connected with said shaft.

In testimony whereof, I hereunto afiix my signature in the presence oftwo witnesses.

. ALANSON P. BRUSH.

'Witnesses t A. H. 'NAcKEn, E, L. THURSTON.

